1. Field of the Invention
The present invention relates generally to a fire tube water heater/heating boiler having a pressurized, submerged combustion chamber and curved, submerged fire tubes, the flue products produced within the fire tubes being cooled below their dew point, causing water vapor normally entrained in combustion gases to condense to a liquid on the heating surfaces of the fire tubes.
2. Description of the Prior Art
In conventional gas/oil fired water heaters, hot gas flows through a series of vertically mounted tubes which are mounted in vertical fashion between top and bottom support plates within the water heater tank. Water flows into and out of a chamber located between the support plates and contacts and circulates about the exterior of the vertical tubes to effect heat transfer to heat the water.
Typical prior art gas/oil fired water heaters featured non-pressurized external combustion chambers. The location of the combustion chamber on the exterior of the water heater resulted in lost heat and lower combustion efficiency. The tubes and support plates were not easily accessible and required disassembly of the entire tank for maintenance and replacement.
U.S. Pat. No. 4,465,024, issued Aug. 14, 1984, to Charles L. Adams, and assigned to the assignee of the present invention introduced a new style water heater to the industry with a submerged, pressurized combustion chamber so that all combustion occurred in the water heater tank interior in a chamber surrounded by water, thereby reducing heat loss and increasing efficiency. However, the combustion chamber and burner assembly were typically horizontally mounted and the design was not a “condensing” design. The outer body of the water heater was formed of metal.
Despite the advantages offered by the design shown in U.S. Pat. No. 4,465,024, a need has continued to exist for a “condensing” water heater design which has improved packaging features including the provision of a synthetic, rotomolded jacket and enclosures.
A need has also continued to exist for such an improved water heater design having a high efficiency heat exchanger with an up-firing central combustion chamber and with improvements in the fire tubes and burner mounting assemblies.
A need has also existed for such an improved water heater design which facilitates access to the internal components of the device for maintenance or repair operations.